RAFT polymerization of dimethyl(methacryloyloxy)methyl phosphonate and its phosphonic acid derivative: a new opportunity for phosphorus-based materials

Abstract

The RAFT polymerization of dimethyl(methacryloyloxy)methyl phosphonate (MAPC1) using dithioester chain transfer agents is reported for the first time to our knowledge in the literature. Poly(dimethyl(methacryloyloxy)methyl phosphonate) (PMAPC1) was synthesized in DMF at 70 °C with a good control over the molecular weight, the latter ranging from 8000 to 24 000 g mol⁻¹. Polymers were characterized by ¹H and ³¹P NMR, and size exclusion chromatography using both refractive index and triple detection. The effect of the solvent was also investigated. We demonstrated that polarity had an effect on the control of the polymerization as low polarity led to low polymerization rate and termination reactions whereas very high polarity resulted in high polymerization rate but also transfer reactions. Additionally, we showed that it was possible to restart the RAFT polymerization from a PMAPC1 macrochain transfer agent. PMAPC1 was hydrolyzed to afford poly((methacryloyloxy)methyl phosphonic acid) (hPMAPC1), whose pK_a values were determined. Finally, we achieved the controlled RAFT polymerization of the (methacryloyloxy)methyl phosphonic acid (hMAPC1). The easy obtaining of PMAPC1 and hPMAPC1 opens the way to the synthesis of complex polymer architectures.